Protects from Battery Polarity Reversal - This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity. The N-channel FET connects the electronic device to the battery only when the polarity is correct. The circuit shown was . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

MOSFET_Temperature_Sensor - Recently I was asked by a company to discover why one of their products failed to operate properly in cold temperatures. Two n-channel MOSFETs and a few resistors are wired to form a flip/flop latch circuit. Each time the pushbutton switch is pressed, the circuit changes state and remains in that state until another activation of the switch. . . . Dave Johnson, Lubbock TX (December 1, 2010)-DC Magazine - Issue 14 Dec 2010

Mini-box 2W Amplifier - This amplifier was designed to be self-contained in a small loudspeaker box. It can be feed by Walkman, Mini-Disc, iPod and CD players, computers and similar devices fitted with line or headphone output. Of course, in most cases you will have to make two boxes to obtain stereo __ Contact: Flavio Dellepiane, fladello @ tin.it

MOSFET based H-Bridge controller for DC Motors - To turn on any of the MOSFETs properly in your circuit, the gate voltage has to be significantly higher than the source voltage. For the lower position devices Q2 and Q4, the sources are grounded to 0V therefore they can easily turn on into "saturation" by applying a gate voltage of a few volts above ground.

MOSFET Beats Murphy's Law - 12/22/94 EDN-Design Ideas - Consider it Murphy's Law: You buy two 15V supplies or one ±15V dual supply to power some op amps. Then, when the last QA inspector or first customer flips the switch, the power supply hangs up. This hang-up occurs because the positive supply yanks its output to positive. The negative supply reads this output as a reverse polarity before it has a chance to start up. So, the supply's negative regulator gives up. __ Circuit Design by Phil Harvey, Technology Integration Inc, Bedford, MA

MOSFET H Bridge - Schematic only - no circuit desciption included __ Designed by Eugene Blanchard

MOSFET LDO Voltage Regulator - This circuit has excellent voltage regulation, due to positive feedback through R2 however the circuit must be started up. This is done by Q4 and Q5. If the circuit does not need to be started under load, Q4, Q5, and R6 can be deleted. You must then pl __ Designed by Andrew R. Morris

MOSFET PaIR makes Simple Circuit SPDT Switch - 12/09/99 EDN-Design Ideas - Ith an n-and p-channel MOSFET, you can easily implement a single-pole double-throw (SPDT) switch to isolate part of a circuit and power it from a secondary supplyPDF has several circuits, scroll for this one. __ Circuit Design by Howard Chen, Vishay Siliconix, Santa Clara, CA

MOSFET Quashes Power Resistor - 06/09/94 EDN-Design Ideas - At power-on, off-line power supplies use a resistor to provide start-up current for the PWM IC, current that is necessary to start driving the power switch. After a few periods, an auxiliary winding delivers a sufficient voltage to power the IC. Unfortunately, the start-up resistor dissipates heat and __ Circuit Design by Christophe Basso , European Synchrotron Radiation Facility, Grenoble, France

MOSFET Replaces Switch - 01/20/94 EDN-Design Ideas - By using a cheap, readily available MOSFET, you can use a single-pole switch to turn a bipolar power supply on and off without consuming extra power. In Fig1, the switch simply controls the MOSFET gate, which swit __ Circuit Design by Malcolm Watts, Wellington Polytechnic, Wellington, New Zealand

MOSFET Replaces Switch - 02/03/94 EDN-Design Ideas - By using a cheap, readily available MOSFET, you can use a single-pole switch to turn a bipolar power supply on and off without consuming extra power. In Fig 1, the switch simply controls the MOSFET gate, which switches on the negative supply. Resistor R, which can be several __ Circuit Design by Malcolm Watts, Wellington Polytechnic, Wellington, New Zealand

MOSFET serves as Ultrafast Plate Driver - 10/03/02 EDN-Design Ideas - The circuit in Figure 1 provIdeas a 20-MHz square wave across a set of highly capacitive ion-deflection plates in an experimental instrument. To get the required deflection, the plate voltage must be 20 to 30V, much higher voltage than conventional logic or driver families can provide __ Circuit Design by Clive Bolton, Bolton Engineering Inc, Melrose, MA

MOSFET shunt regulator substitutes for series regulator - 25-Nov-04 EDN-Design Ideas - You would normally use a series linear regulator or a DC/DC converter to obtain 3V dc from a higher supply. However, when breadboarding a concept, you may be able to use a shunt regulator, especially if a series regulator of the correct voltage is unavailable. The MOSFET in Figure 1 can replace a zener diode in a shunt regulator and provide lower output impedance than a zener diode __ Circuit Design by Stuart R Michaels, SRM Consulting

MOSFET switch provides efficient ac/DC conversion - 02/17/00 EDN-Design Ideas - Occasionally, you have access to a transformer for powering a dc circuit, but its output voltage is much higher than that required for the dc voltage. The full-wave-rectified and filtered output of an ac input voltage V X , is V DC =1.414V X-2V F , where V F is the forward drop in the rectifier (approximately 0.7V) . __ Circuit Design by Spehro Pephany, Trexon Inc, Toronto, ON, Canada

MOSFET Tester - This testing procedure is for use with a digital multimeter in the diode test-range with a minimum of 3.3 volt over d. u. t. (Tony van Roon's diode-under-test) . If your multi-meter is less than that it will not do the test. Check your meter manual for the specs. __ Designed by Tony van Roon VA3AVR

MOSFET UPS Regulator's Output Current - 02/01/96 EDN-Design Ideas - Use a current mirror and a power MOSFET to increase the output-current capability of an IC-voltage regulator. __ Circuit Design by Robert Buono, Universal Sonics Mahwah, NJ

MOSFET, Inverter 12 volt unit - A Very Reliable, Efficient and Practical Design. Do Not ask how to Build this for Power ratings over 1000 watts, That is NOT Practical. __ Designed by G.L. Chemelec

MOSFET-Based Preamplifier for FM Radio Dxing - FM transmissions can be received within a range of 40 km. If you are in fringe areas, you may get a very weak signal. FM DXing refers to hearing distant stations...__ Electronics Projects for You

MOSFETs Reduce Crosstalk Effects On Analog Switches - 02/17/97 EDN-Design Ideas - Some cost-effective analog multiplexer/demultiplexer ICs, such as the CD4053 and CD4066, find frequent use as signal distributors. These digitally controlled analog switches have low on-resistance. However, with all channels in the same package, crosstalk can be annoying and unavoidable. Figure 1 provIdeas a cost-effective and viable method of solving this problem. By simply adding some n-channel MOSFETs, such as the 2N7002 or 2N7000, the crosstalk effect becomes negligible. When the Channel Select signal is high, the CD4053's input pins A, B, and C assume a level of nearly 0V. __ Circuit Design by Stanley Chen, Global Mixed-Mode Technology, Taipei, Taiwan

MOSFET_Temperature_Sensor - Recently I was asked by a company to discover why one of their products failed to operate properly in cold temperatures. Two n-channel MOSFETs and a few resistors are wired to form a flip/flop latch circuit. Each time the pushbutton switch is pressed, the circuit changes state and remains in that state until another activation of the switch. . . . Dave Johnson, Lubbock TX (December 1, 2010)-DC Magazine - Issue 14 Dec 2010

Power MOSFET is Core of Regulated-DC Electronic LoA - D - 03/17/05 EDN-Design Ideas - Designers use electronic dc loads for testing power supplies and sources, such as solar arrays or batteries, but commercial ones are often expensive. By using a power MOSFET in its linear region, you can build your own (Figure 1) . It uses two simple feedback loops to allow the transistors to work as a current drain in current-regulation mode or as a voltage source in voltage-regu __ Circuit Design by Ausias Garrigós and José M Blanes, University Miguel Hernández, Electronic Technology Division, Elche, Spain

Power Resistor Varies In Value - 07/28/11 EDN-Design Ideas - Under controlled conditions, a MOSFET can function as a variable power resistor. Testing power supplies or discharging batteries usually requires a constant-current load. Sometimes, however, you must study the behavior when the load is a resistor. Using a high-power potentiometer is an expensive approach that might not be worth the cost. The circuit in Figure 1, which performs like a high-power resistor that connects between P1 and P2, provIdeas an alternative approach __ Circuit Design by Bogdan Raducanu, Bucharest, Romania

Protect MOSFETs In Heavy-Duty Inductive Switched-Modes - 02/03/11 EDN-Design Ideas - Measure peak currents and use ac coupling to prevent FET burnout. The MOSFET power switch is commonly the most vulnerable part of a new switched-mode high-power circuit. One threat for this device is exceeding the value of the maximum allowed pulse current. You cannot exceed this limit, even for pulse durations as short as 10 nsec. You could still thermally damage the MOSFET with a high duty cycle even when the drain-to-source current has a value between the peak and the dc ratings. __ Circuit Design by Marián tofka, Slovak University of Technology, Bratislava, Slovakia

Protects from Battery Polarity Reversal - This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity. The N-channel FET connects the electronic device to the battery only when the polarity is correct. The circuit shown was . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002